After less than a year on the job, Larry Tolliver is calling it quits as chief of the troubled Anne Arundel County Police Department.

Tolliver, 67, said his resignation — or "return to retirement," as he called it — will take effect May 21.

"I am resigning today because the department needs a chief who can focus solely on the department's mission, something that is challenging to do in the current environment," Tolliver wrote in a statement Tuesday.

Tolliver said his resignation was not motivated by a recent investigation into allegations he used anti-gay slurs and retaliated against officers by changing their work assignments. He acknowledged using an "insensitive term in one joking conversation" and said he later apologized, and added the county Department of Personnel determined other complaints were "unfounded."

He said the decision also was not influenced by the fact that County Executive Laura Neuman is bringing in officers from Harford County and Montgomery County to investigate Anne Arundel's department. Tolliver said he welcomes the investigation.

Tolliver said he was spurred to resign following what he described as constant questioning of his leadership, especially through anonymous letters and complaints. He said they took a toll on him, his family and on the department as a whole. He said it was coming at a time when the agency needed to recover from the troubles and problematic atmosphere he found when he became chief last summer.

"It's been ongoing. It needs to stop. The agency needs to cleanse itself," Tolliver said.

The county did not announce who will take over for Tolliver following his departure.

Tolliver said he handed his resignation to Neuman earlier in the day. "She asked me: 'Are you sure this is what you want to do?'" Tolliver said.

Neuman did not respond to an interview request, but posted a note on her county Twitter account saying, "Anne Arundel Police Chief Larry Tolliver submitted his resignation today. … I thank him for his service to the county."

County Councilman Dick Ladd, a Severna Park Republican, said the chief's resignation amid public scrutiny and an investigation may "continue the turbulence" within the agency.

Tolliver arrived on the job last summer amid scandal. Former County Executive John R. Leopold brought him out of retirement to take over for James Teare. Teare resigned following the indictment of Leopold and an investigation into Leopold's use of his police security detail for personal and political activities.

Leopold was later convicted of misconduct in office, resigned and served 30 days in jail. The County Council selected Neuman to complete Leopold's term, which ends in 2014.

When Tolliver was brought in last year, it was his second stint running the department. In 1997, he was hired by then-County Executive John Gary, only to be dismissed a year later by the next executive, Janet S. Owens, after he allowed on-duty officers to appear in print campaign ads for Gary.

Tolliver also led the Maryland State Police as superintendent from 1993 until 1995, and was director of enforcement for the state comptroller from 1999 until 2007.

Ladd said he's sad to see Tolliver go.

"I thought he was making very good progress with the Police Department. People, in large part, were satisfied with what he was doing," Ladd said. "Based on what I knew, I thought he was doing fine."

"We now have to go out and find someone who will come in, and could be Ms. Neuman's selection, but could be faced with the situation of being here for only 16 or 18 months," Ladd said. "It's hard to get someone good to come in."

Councilman Jamie Benoit, who has raised concerns about the department and sent a letter to Neuman last month calling for an investigation of the anti-gay comment and reassignment allegations, said he's hopeful the executive can hire a chief who can start fixing problems in the department.

Benoit said the department's issues predate Tolliver's tenure. He declined to go into specifics, but said the department "is in shambles."

"I think there are systemic problems in our police department that aren't necessarily attributable to one chief or two chiefs. … The county executive will have earned a term of her own if she can get the culture back to where it was," he said.

Councilman Derek Fink, a Pasadena Republican, said Neuman can overcome negative perceptions about the Police Department in hiring a new chief.

"I think it's still a great job. Anne Arundel County is a great county, it's a great place to be. We've got a really good police staff. At the end of the day, we'll find a great candidate," he said.

Dave Daughters, president of the Western District Police-Community Relations Council, said he is "very disappointed" Tolliver decided to call it quits. He called the allegation that Tolliver retaliated against officers who testified against Leopold "ridiculous" and said some of the changes Tolliver made no doubt left some unhappy.

"He was making an effort to improve the department," Daughters said. In addition, he said, "He made himself very visible. He was at community meetings."

Besides looking for a new police chief, the county executive must find a fire chief. The last chief, Robert Ray, resigned May 1. The acting chief is Michael Cox, who has held a number of positions in the department during his more than 25-year career.

A federal jury Wednesday convicted Cornell Louis Robinson, 44, of Washington, D.C., on charges related to the armed carjacking of an Annapolis couple who were about to enter their vehicle to go to the hospital because the woman was in labor.